In the manufacture of some types of electrical assemblies, such as rigid pin-populated printed wiring boards, or backplanes, as many as 10,000 terminal pins are inserted into apertures of each of the backplanes. Backplanes typically have an elongated configuration. For example, one common type of backplane measures eight inches by twenty-two inches. Typically, the spacing between adjacent apertures on each backplane is relatively narrow. For example, the spacing between apertures on backplanes is often as little as 2 mm. Moreover, each terminal pin typically has a cross section of, for example, 0.50 mm.sup.2, except in those cases in which the pin is formed with (1) lateral ears having a push shoulder and (2) an aperture-engaging portion intermediate the ends thereof. In either event, the pin is relatively slender and typically measures from 11 mm to 26 mm in length.
Each of the pins has a slender shank portion which extends from opposite sides of the backplane. After the terminal pins have been assembled into the backplane, the backplane is mounted in a frame where external wiring can be secured to the pins on one side of the backplane commonly referred to as the wiring side. Other printed wiring boards, referred to as circuit packs, have electronic components electrically and mechanically secured thereto and have receptacles secured to one end thereof. The receptacles of these boards ultimately are inserted over selected ones of the pins extending from the other side of the backplane commonly referred to as the component side.
During the insertion of the circuit packs into the backplane and during subsequent handling of the pin-populated backplane, some of the pins may be undesirably broken or bent. Broken or bent pins can lead to assembly complications and thus reduce the value of the backplane.
In particular, since the component side of the pins are destined for insertion into a receptacle, it is important that no broken pins are present in the pin-populated backplane and that the pins are axially straight with respect to the plane of the backplane within an acceptable tolerance. Otherwise, a slightly bent pin on the component side, for example. could be misaligned with its mating aperture in the receptacle. As the receptacle is moved into place, the bent pin would engage the face of the receptacle and would be bent further towards the surface of the backplane thereby failing to provide the required electrical connection. In addition, any broken pin present in the pin-populated backplane would also result in a failure to make the required electrical connection. Therefore, it is desirable to replace any bent or broken pins with new pins.
Replacing broken or bent pins in a backplane is difficult due to a number of reasons. For example, the spacing and size of the pins makes them difficult to manipulate with ordinary tools. In particular, as discussed above the pins are positioned within the backplane on a grid spacing format such that each pin is closely spaced apart from its neighboring pins, often by no more than 2 mm. Consequently, as a result of the pins being so closely arranged, it is very difficult to remove and replace any broken or bent pins from the backplane without disturbing the adjacent pins. In addition, after the backplanes are mounted in an assembly or shelf, the space behind the backplanes is often relatively small. This small space impedes the access to the backplanes, and thus adds to the difficulty in utilizing the appropriate tools to replace broken or bent pins.
Heretofore, the tools utilized to replace broken or bent pins in a backplane have been relatively large and bulky, and thus difficult to manipulate in the above described space limitations. For example, one commercially available tool for inserting a replacement pin into a backplane includes a long cylindrical shaft having a tip adapted to seat the replacement pin. This tool also includes a slide hammer and a handle attached to the cylindrical shaft. To insert the replacement pin into an aperture defined in a backplane, the replacement pin is seated into the tip of the cylindrical shaft and an end of the replacement pin is slightly advanced into the backplane aperture. The technician operating the tool must then grasp the handle thereof with one hand while operating the slide hammer with the other hand. In particular, the slide hammer must be grasped by the technician's other hand and manually moved toward the tip the cylindrical shaft until the slide hammer strikes a stop member positioned on the cylindrical shaft. By striking the aforementioned stop member, the momentum of the slide hammer is transferred to the tip of the cylindrical shaft thereby driving the replacement pin into the connector or header and the backplane aperture. The above described actuation of the slide hammer is then repeated until the replacement pin is driven into place.
While the aforementioned tool allows the technician to insert a replacement pin into a backplane, it is relatively large and cumbersome. In particular, the slide hammer is rather large and heavy, and thus makes the tool difficult to manipulate in the above described confined spaces. In addition, the tool requires two hands to operate (i.e. the technician must hold the tool with one hand while operating the slide hammer with his or her other hand) which is inconvenient for the technician replacing the pin. Moreover, the tool is relatively expensive and thus adds to the cost of maintaining backplanes.
Therefore, it is desirable to provide an arrangement and method for repairing an electrical assembly which overcomes one or more of the above discussed problems.